If you do this on steam the easiest way i have found its to have 2x steam accounts(new copy/key on each).. when you want to play one character you launch that steam account and right click on operation arrowhead and click the reinstall battleye client. that will update your registry to the CD key for that account, then just launch the game with six laucher you do not need to change/add a new character profile it just works or it does for me :) (edit - this did work until todays battleye update!)